Mineral Like (Natural Glass)

Green glassy slag or manufactured glass bead

Noncrystalline silicate glass; likely industrial glass/slag, not a true mineral

Quartz (Gray or Smoky variety)

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Smoky Quartz

Silicon Dioxide (SiO2)

Quartz (Citrine variety)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (Fe2O3 stained)

Obsidian (black volcanic glass)

Obsidian; predominantly rhyolitic volcanic glass, mainly SiO₂ with minor feldspar, quartz, and iron oxides

Cat's Eye Moonstone (Simulated/Synthetic or natural Cat's Eye Quartz/Glass)

There is no single scientific name. The appearance suggests either: Moonstone (feldspar group), Cat's Eye Quartz (SiO2), Apatite (Ca5(PO4)3(F,Cl,OH)), or most likely a synthetic material such as Fiber Optic Glass or 'Opalite' (a type of glass).

Goldstone (Brown)

Aventurine glass

Smoky Quartz

Smoky Quartz (Silicon Dioxide, SiO2)

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Sandstone

Sedimentary Rock (Quartz arenite)

Smoky Quartz

Silicon Dioxide (SiO2)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Amethyst geode

Quartz, SiO₂; purple variety amethyst, commonly a drusy-lined geode

Lemon Quartz (or Yellow Calcite)

Silicon Dioxide (SiO2) / Calcium Carbonate (CaCO3)

Sandstone

Arenite (SiO2 based)

Green Aventurine

Silicon Dioxide (Quartz) with inclusions of Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)

Green Fluorite (likely synthetic or heat-treated for jewelry)

Calcium Fluoride (CaF2)

Opalite

Synthetic Opalite (Man-made glass)

Green Aventurine

Aventurine Quartz (SiO2 + Fuchsite inclusions)

Milky Quartz with Iron Inclusions

Silicon Dioxide (SiO2) with Hematite/Limonite

Sandstone

Arenite (SiO2 with minor iron oxides)

Quartz (Variety: Citrine or Iron-stained Quartz)

Silicon Dioxide (SiO2)

Fulgurite

Fulgurite (Lechatelierite-rich variety)

Sandstone

Arenite (SiO2 based)

Smoky Quartz with Calcite/Quartz Veining

Silicon Dioxide (SiO2)

Smoky Quartz (Rough)

Silicon Dioxide (SiO2)

Obsidian

Volcanic glass

Sandstone

Arenite (primarily Quartz, SiO2)

Tektite (Indochinite)

Tektite (Silica-rich natural glass)

Goldstone and pink quartz bead strands

Goldstone is aventurescent copper-bearing glass; pink beads are likely rose quartz (SiO₂), though dyed or glass imitations are possible

Clear Quartz

Silicon dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Clear Quartz Crystal

Quartz (Silicon Dioxide, SiO2)

Druzy Quartz (Botryoidal)

Silicon Dioxide (SiO2)

Aventurine Quartz

Silicon Dioxide (SiO2) with Fuchsite inclusions

Quartz pebble (Agate / Chalcedony)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Sandstone

Sedimentary quartz arenite